1. Field of the Invention
This invention relates to audio amplifier circuits and more particularly to bridge amplifier circuits.
2. Description of the Prior Art
Audio bridge amplifiers are well known in the art. Most, if not all, of the contemporary bridge amplifiers are comprised of at least two operational amplifiers using coupling capacitors and some direct current adjustment circuitry for adjusting and matching components to reduce the output offset voltage of the amplifier. It is desirous to reduce the output voltage offset in order to reduce the power consumption of the bridge amplifier. It is also desired to produce the bridge amplifier in monolithic integrated circuit form to maximize circuit efficiency and to reduce production costs.
Because many prior art bridge amplifiers require large capacitors and other external circuits for adjustments, the cost of these external components offset any practical savings which may result by fabricating the amplifier in monolithic form. Thus, a need exists to reduce or eliminate as many required external components as possible while maintaining the output offset voltage to a minimal level.